Duct joint construction



Oct. 21, 1941. w. H. GRAY 2,260,221

DUCT JOINT co1-xsTRUcTIoN Filed May 25, 1940 2 Sheets-sheet 1 MZZZLQWZ. 64mg Oct. 21, 1941. w. H. GRAY 2,260,221

DUCT JOINT CONSTRUCTION Filed May 25, 1940 2 Sheets-Sheet 2 Patented Oct. 21, 1941 DUCT JOINT CONSTRUCTION William H. Gray, Rochester, N. Y., assigner to Gray Metal Products, Inc., Rochester, N. Y., a corporation of New York Application May 25, 1940, Serial No. 337,274

2 Claims.

The improved duct joint comprising the present invention is primarily adapted for use in connection with warm air heating and air conditioning installations. The principles of the invention, however, are applicable to other uses and the present duct joint may be employedV in connection with all manner of vfurnace and stove pipe, air ducts and tunnels, etc., particularly where the installations are comprised of sheet metal. A y

In installations of this character, where a branch is made from a main trunk line, many difficulties are encountered in making the mounting and in providing an air-tight joint at the location of the branch. This is particularly true where the branch or take-off is made at the end of a conduit section and a corresponding reduction in the sizeof the main trunk lineis effected, or where several branches `or take-off connections are made at the ultimate end of the main trunk line. v

In such instances it has been customary, where installations are made on the job, for the Workman to pry the usual external locking cleat provided at one end of each trunk line conduit section outwardly and notch the inner rim of the section at the proper place to provide a clearance for the adjacent rim portions of the branch conduit and reduced trunk line section. Such a'method of installation is unsatisfactory, first,l in that after the locking Vcleat has-once been bent out of its normal plane it is diicult to again restore it to its original position. Even in an instance where the operator is able to reach the length of the section with a dolly bar tov reinforce the locking cleat, the locking cleat cane not be effectively restored to its original position and the resultant joint is frequently unsightly and not air tight. Secondly, unless the locking cleat is bent outwardly at ninety degrees or more from its normal position, the operator is unable to reach with his shears the bottom ofthe U- shaped retaining Docket or seat provided between the cleat and body of the conduit section and as a consequence the notch thus formedA in the in'- stallation process is not sufficiently deep to accommodate the edges or rim portions of the branch and reduced trunk line conduit sections.

The present invention is designed to overcome the above-noted limitations that are attendant upon the use of present-day conventional warm air and air conditioning system installations and toward this end contemplates the provision of preformed units which may be quickly and easily assembled on the job in a very secure manner and without the use of tools. Installations made according to the present invention require no bending 'of the usual locking cleat, and, when assembled, are entirely air-tight and rigid and present no visible evidence of the pre-notching operations resorted to in the manufacture of the units. Furthermore, such installations may be made by unskilled operators with very little or no opportunity for improper assembly of the various parts.

"These being the principal objects of the invention, `another object thereof is to provide an installation o-f the character set forth above which may be built up on the job according to the various requirements and conditions Iimposed by the particular job. A related object is to proi vide an installation consisting of vpreformed units which maybel constructed according to` standard sizes, the units being capable of being fitted together in several different wa'ys and in such a manner that the entire installation-is easy to balance. Y i The provision of yan installation of this' character which is possessed of no pivoted Vor other parts which are movable relative vto eachother, at least insofar as Vthe locking'of ythe sections together is concerned; one which is rugged and durable andwhich consequently `is unlikely to get out `of orderand which willwithstand rough usage, and which may bemanufactured ata relatively low cost, and one which otherwiselis well adapted to perform the services required of it, are further desiderata that have been borne in mind in the production'and development of 'the present invention.

' Other objects and advantagesof the invention Figure 1 is a fragmentary side elevational vi'ew partly in section of van air duct installation manufactured and assembled according to the principles of the present invention. ,Y Y' Figure 2 is a sectional view taken vsubstantially along the line 2-2 of Figure 1.`

Figure 3 is a fragmentary perspective vieWof the Aair duct installation. f

Figure 4 is a fragmentary perspective view partly in section of a conduit or :duct `section' illustrating certain locking features employed in connection with the invention. r

` Figure 5 is a fragmentary sectional view taken transversely through an interlocking seam existvmore or less schematic in their representation for the purpose of illustrating a typical or pre1.

. the slots 32 to further facilitate tearing off or removal of the bridge portions 34.

ferred embodiment of the invention. For examA c 1 ple, purely for illustrative purposesthe improved g n duct joint construction is shown in connection with a rectangular main trunkline including an initial trunk line section A and a trunk line..

section B of reduced cross-sectional area and an' adaptor boot C having a connection for a roundv branch line conduit. It will be understood, how- .Y ever, that the improvedduct joint construction" is capable of use 'in all manner of installations and isadaptable for use in connection with long# way and shortwayelbow connections, angle con-I nections, increaser or reducer connections, damp-` er sections, register units, adaptor and trans-` former connections, 4and a great variety of other connections regardless of the cross-sectional contour lof'these parts.

Referring now to Figures 1 and 2, the main trunk line or distributor duct sections A and B each includes longitudinal and transverse Walls I0 and I2 which, at one end of the section, are formed with generally S-shaped seams I3 that are formed by first bending the margins of the walls during formation of the section from its blank as at I4 (Figure 5) to .provide a locking bead, then bending the outer edge regions of the walls back -upon themselves to provide a cleat kportion I6, and finally giving the walls a reverse l C are .inserted into their respective pocketsy 'I8V withy the inner transverse walls I2, 22v of the sections'B and C, respectively, occupying positions in substantial contiguity.

A plurality of locking protuberancesV 24 varev formedl on the various walls of :the'sections B and Cadjacent the juncture with the section A and are vadapted lto :extend behindthe locking bead as shown in Figure 2,V so thatonce the sections' are assembled, they are locked in posi-l tion. *'The locking protuberances may beformed by a' stamping andk pressing operation on .the metal of the Walls of the various sections.

. In order to accommodate Athe adjacent and contiguous transverse edges of l the walls 'I2 and 22,' aj pair ofopposed open-ended slots 30 are provided through the .two inner folds of the longitudinal seams I3 of .the section A, Vthe slots extending from the .rim of the section A to the bottom of the pockets I8.' A

In the manufacture of the sections A, B andl C or ofother units such as angle pieces, elbows, damper sections or units, register sections or units and the like, accommodations for aplurality of pairs of .the slots 30 are provided for Walls of said section each having a reverse bend by forming a plurality of pairs of spaced, axially aligned rectangular closed-end slots 32 (Figure 6) vin the blank B from which the section or unit is formed. After the blank B has been bent to iinal shape, the slots 32 of each pair come into register as shown in Figure 3, leaving a bridge portion 34 which may be cut away by the operator prior to assembling the various sections. If desired, the original blank B may be scored along lines I-I (Figure 6) connecting g Inorder'to accommodate the engineering requirements of various types of installations, the

blank is Vso formed that the various pairs of opposed composite slots 32 will occur in the completed unit at spaced regions which are standard distances removed from the corners of the units.

, For example, these slots 32 may be provided both in the longitudinal walls and in the transverse walls of the units at 4, Sand 12 inch distances inward from the corners of the larger sizes of main trunk line conduit sections. For intermediate'size trunk line conduitsections, the slots may be formed at 4 and 8 inch distances inward from the corners, while, for -srnallsizesof mainof.V Neither is it necessary that his shears cut to the-'bottom of the pocket I8 to secure a deep enough slot for proper intertting v of the parts.

Furthermore, should an operator, by a mscalculation or error in judgment, remove the'wrongY bridge piece 34, no damage will have resulted to the :structure as the slot 30 thus formed is concealed in the assembled structure and provides'V noopen vent'for vescape cf air. It is also to be `noted that the chance of 'error in cutting the notches 30 is materially lessened inasmuch as the composite closed-end slots 32 inv effect provide am. easure of the required distance.

Thus, not only is it unnecessary for the operator toutilize special tools in the 'installation ofl j the parts, but he is'not even required to utilize a measuring rule, The invention is not to be limited to the exact arrangement of parts shown in the accompanying drawings or described in the specification, 'as various changes in the details of construction maybe resorted to` without departing fromthe spirit of the invention. For example, while the cleat portions I6 are shown as being 'formed in tegral with the edge portion of the conduit secL tions, these cleat portions may,` if desired, be separately formed and soldered or otherwise 'se-Vv cured inl position. Likewise, the double rein-l forced reversed edge portion of` the conduit sec tions'may, if desired, be formedof separate members soldered or otherwise secured. to each other. Only insofar as the invention has been particularly pointed out in the accompanying claims is the same to be limited.V Y

` What is claimed is: Y

1. An open-ended sheet metal conduit section of rectilinear configuration in cross section, the

atits edge portion providing anVV outer locking'V cleat and an inner double wall vreinforced edge'l portion, said cleats and edge portions forming therebetween pockets adapted to receive therein the walls of adjacent conductor sections in an assembly installation, there being a pair of opposed slots in at least one opposed pair of walls in the reinforced edge portions thereof and spaced inwardly from the edges of said walls by a bridge portion adapted to be cut away prior to the assembly operation to form open-ended notches adapted to receive therein the corners of the adjacent conductor sections.

2. An open-ended sheet metal conduit section of rectangular configuration in cross section, the walls of said section each having a reverse bend at its edge portion providing an outer locking cleat and an inner double wall reinforced edge portion, said cleats and edge portions forming therebetween pockets adapted to receive therein the walls of adjacent conductor sections in an assembly installation, there being a plurality of pairs of opposed slots in each opposed pair of Walls in the reinforced edge portions thereof, said slots being spaced inwardly from the edges of said walls by a bridge portion adapted to be cut away prior to the assembly operation to form open-ended notches for the reception therein of the corners of the adjacent conductor sections,

\ WILLIAM H. GRAY. 

